PTL 1 discloses a method of displaying a robot malfunction occurrence history. A conventional method of displaying a robot malfunction occurrence history will be described with reference to FIG. 11, FIG. 12, and FIG. 13. FIG. 11 is a schematic flowchart of conventional sampling data memorization. FIG. 12 is a conceptual chart depicting a configuration of a conventional data memory file. FIG. 13 is an exemplary graph of conventional data display.
As depicted in FIG. 11, the conventional sampling data memorization includes step S901 to step S909.
Step S901 includes determining whether or not malfunction detection flag F has an initial value of “zero”. If malfunction detection flag F is not “zero”, an alarm is occurring. The sampling data memorization accordingly ends. If malfunction detection flag F is “zero”, the flow proceeds to subsequent step S902.
Step S902 includes reading a torque command current value. The flow then proceeds to subsequent step S903.
Step S903 includes adding one to address search index i. Address search index i has an initial value of “zero”. The flow then proceeds to subsequent step S904.
Step S904 includes determining whether or not address search index i obtained after the addition of one exceeds n. The flow proceeds to step S906 if address search index i does not exceed n. If address search index i exceeds n, address search index i is set to “one” (step S905). The flow then proceeds to step S906.
In step S906, the torque command current value read in step S902 is memorized as sampling data corresponding to address search index i in the data memory file. The flow then proceeds to subsequent step S907.
In step S907, address search index i is memorized in final record address memory register Pe. The flow then proceeds to subsequent step S908.
Step S908 includes determining whether or not an alarm is occurring. If an alarm is occurring, malfunction detection flag F is set to “one” (step S909). The sampling data memorization then ends. If no alarm is occurring, the sampling data memorization ends without including step S909.
The sampling data memorization (step S901 to step S909) is repeated at predetermined period Δt to generate data memory file 910 as indicated in FIG. 12. As in FIG. 12, data memory file 910 includes torque command sampling data of which number is limited to address number n. The oldest sampling data is updated with the latest sampling data.
A torque command before alarm occurrence by time corresponding to n·Δt can be indicated in accordance with data memory file 910, as in the graph of FIG. 13 having a transverse axis for time t and an ordinate axis for tor torque command T.
PTL 2 and PTL 3 also refer to storing sampling data in case of alarm occurrence.